Tens of thousands of patients are diagnosed with colorectal cancer each year. Approximately twenty percent of those patients will experience locally recurrent tumors. Conventional clinical standard-of-care involves adjuvant chemoradiation therapy to reduce tumor burden, followed by pre-operative treatment planning with manual inspection of pre-surgical magnetic resonance imaging (MRI) imagery. Pre-operative planning in colorectal cancer is highly dependent on the extent of tumor invasion into the mesorectum and perirectal fat. However, the measure of tumor distance to the mesorectal wall, defined as the circumferential resection margin (CRM), is only measured after surgery in conventional approaches. Conventional approaches thus delay adjuvant intervention that could improve patient outcomes.
Conventional approaches to colorectal treatment planning involve manual inspection of pre-operative MRI imagery. However, conventional approaches lack definitively identified imaging characteristics of treatment response, which leads to sub-optimal surgical planning as well as misdiagnosis of complete or incomplete treatment response. Thus, almost all colorectal patients subject to conventional approaches undergo some form of colorectal excision surgery, regardless of the stage of the cancer or the effectiveness of treatment. In the United States alone, up to 8,000, or twenty percent of colorectal patients are subjected to morbid total mesorectal excision, despite demonstrating pathologic complete response to pre-surgical neoadjuvent chemotherapy.
Conventional approaches to colorectal treatment planning may involve expert evaluation of pre-surgical restaging MRI. Expert evaluation of pre-surgical restaging MRI is qualitative and has no standardized reporting system. Expert evaluation of pre-surgical restaging MRI is thus also prone to inter-operator variability. Furthermore, identifying the extent of tumor invasion using pre-surgical restaging MRI is subjective and depends on the individual expert's skill at accurately identifying the extent of tumor invasion versus confounding treatment effects in vivo.